Airbag module cover

ABSTRACT

A cover for an airbag module includes at least a first layer, a second layer, and a third layer. The first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 10/944,773, filed Sep. 21, 2004.

BACKGROUND OF THE INVENTION

The present invention relates to an airbag module and, more particularly, to an airbag module cover that includes an outer surface that forms part of a vehicle instrument panel.

In an airbag device for a vehicle, an airbag is typically accommodated in an airbag module that includes a retainer covered by a module cover. The retainer is connected to the vehicle structure, and the outer surface of the module cover faces into the vehicle passenger compartment. For a driver airbag device, the airbag module is mounted to a steering wheel of a vehicle. For a passenger airbag device, the airbag module is mounted to an instrument panel of the vehicle. In the event of a vehicle emergency such as a collision, an inflator in the airbag module delivers inflation gas into the airbag thereby inflating the airbag. As the airbag inflates, the airbag exerts pressure on the module cover. When sufficient pressure is exerted on the module cover, the cover ruptures and opens toward the inside of the vehicle cabin thereby allowing the airbag to be inflated inside the vehicle cabin to protect a vehicle occupant.

One disadvantage of conventional airbag modules is that the module cover must be made of materials that can be configured to rupture and that can withstand high airbag deployment temperatures. As a result, conventional module covers typically include an injection molded base layer having a pre-weakened portion such as a tear line groove that ruptures or breaks when sufficient pressure is exerted on the module cover by the inflating airbag. Conventional module covers generally also include a surface sheet disposed on the base layer so that the outer surface of the module cover matches the appearance and feel of the vehicle instrument panel. The surface sheet may include a lower layer formed of a thermally resistant resin, a middle layer formed of a soft foamed resin, and an outer decorative layer formed of a thermoplastic elastomer (TPE). The TPE can be, for example, polyolefin based (TPO), polystyrene based (TPS), polyvinyl chloride based, polyester based, polyamide based, or urethane based.

As a result of the above requirements and construction, the design and appearance (e.g., texture, color, pattern, surface finish) of conventional module covers is limited. Moreover, the thermoplastic elastomers forming the decorative layer are not well suited for application of coatings and paints thereby further limiting the appearance of the module cover so that desired customer finishes often can not be achieved.

SUMMARY OF THE INVENTION

According to one embodiment of the present invention, cover for an airbag module is provided. The cover includes at least a first layer, a second layer, and a third layer. The first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle.

According to another embodiment of the present invention, a cover for an airbag module includes a base layer and a substrate disposed on the base layer. The substrate includes a pair of panels each including an outer layer.

According to another embodiment of the invention, an airbag module for a vehicle includes an airbag, an inflator, and a cover. The cover includes a top surface facing toward an interior of the vehicle. The top surface comprises metal.

According to another embodiment of the invention, an airbag module is configured to be positioned in a vehicle so that a cover of the module forms a portion of the vehicle instrument panel. The cover includes a metal top layer configured to separate into at least two pieces to allow an airbag to deploy therethrough.

According to yet another embodiment of the invention, a method of forming a cover for an airbag module includes providing a base layer having a pre-weakened portion for deploying an airbag, providing a substrate having a first panel and a second panel, providing a first metal sheet and a second metal sheet, wrapping the first metal sheet around the first panel so that the first metal sheet substantially covers front and side surfaces of the first panel, wrapping the second metal sheet around the second panel so that the second metal sheet substantially covers front and side surfaces of the second panel, and attaching the first and second panels to the base layer.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate a preferred embodiment of the invention and together with the description, serve to explain principles of the invention.

FIG. 1 is a cross sectional side view of an embodiment of an airbag module according to the present invention.

FIG. 2 is a top plan view of a module cover of the airbag module of FIG. 1.

FIG. 3A is a perspective view of a substrate and a surface layer of the module cover of FIG. 2 showing the surface layer prior to installation on the substrate.

FIG. 3B is a cross sectional view taken along the line A-A of FIG. 3A showing the surface layer installed on the substrate.

FIG. 3C is a cross sectional view taken along the line B-B of FIG. 3A showing the surface layer installed on the substrate.

FIG. 4 is a perspective view of the airbag module of FIG. 1 installed in a vehicle instrument panel.

FIG. 5 is a cross sectional side view of an embodiment of an airbag module according to the present invention.

FIG. 6 is a cross sectional side view of a cover layer of FIG. 5.

FIG. 7 is a cross sectional side view according to an embodiment of the present invention showing attachment of an airbag module cover layer to a base layer.

FIG. 8 is a cross sectional side view of an embodiment of an airbag module according to the present invention.

DETAILED DESCRIPTION

FIGS. 1-4 show an embodiment of an airbag module 100 according to the present invention. The airbag module 100 includes an airbag 10, an inflator 20, a retainer 30, and a module cover 40.

The airbag 10, the inflator 20, and the retainer 30 are not specific to the present invention and may be any airbag, inflator, and/or retainer generally known to those of skill in the art. Similarly, the airbag 10, the inflator 20, the retainer 30, and the module cover 40 may be connected together and installed in a vehicle using known methods and components. For example, the retainer 30 may be configured to be connected to the vehicle structure. The airbag 10 and the inflator 20 may be secured to the retainer 30. The retainer 30 and the module cover 40 may be connected together so that an enclosure 35 is formed between the retainer 30 and the module cover 40. The airbag 10 is disposed in the enclosure 35 in a folded state (shown in FIG. 1) and is operatively connected to the inflator 20. During a vehicle emergency, the inflator 20 generates inflation gas, which flows into the airbag 10 to inflate the airbag 10.

According to an embodiment, the module cover 40 includes a skirt 42 and a lid 44. The skirt 42 projects from a rear (or inner) surface of the lid 44 as shown in FIG. 1. As is well known, the skirt 42 may be, for example, a continuous member or may include a plurality of separate leg members. The skirt 42 provides an interface for connecting the module cover 40 to the retainer 30. For example, the skirt 42 may be connected to a corresponding connector portion 32 of the retainer 30 in any manner known to those of skill in the art.

The lid 44 of the module cover 40 forms part of a vehicle instrument panel 200 when the airbag module 100 is installed in a vehicle. As shown in FIG. 5, a front (or outer) surface of the lid 44 is substantially aligned with an outer surface 270 of the instrument panel 200 and faces toward an interior 300 of the vehicle (i.e., into a vehicle passenger compartment). The lid 44 includes a base layer 50 and a cover layer 60. The base layer 50 underlies the cover layer 60 and forms the rear surface of the lid 44. The cover layer 60 is attached to the base layer 50 and forms the front surface of the lid 44 as shown in FIG. 1.

The cover layer 60 may be attached to the base layer 50 using attachment hardware or an adhesive. The cover layer 60 may also be configured to snap onto the base layer 50. In an exemplary embodiment, the base layer 50 includes a plurality of through holes, and the cover layer 60 includes corresponding bosses B. The cover layer 60 is connected to the base layer 50 by inserting the bosses B into the through holes and post-forming (e.g., melting) the bosses B to retain the cover layer 60 on the base layer 50 as shown in FIG. 7. In another exemplary embodiment, the cover layer 60 is secured to the base layer 50 by tabs T. As shown in FIG. 6, the tabs T are disposed on a bracket 67 (e.g., a stamped metal bracket). The bracket 67 may be inserted into recesses (not shown) in the substrate 65 or molded into the substrate 65 so that the tabs T project from the substrate 65. The base layer 50 includes corresponding through holes into which the tabs T are inserted. As shown in FIG. 5, the tabs T are then bent over to mechanically secure the cover layer 65 to the base layer 50. The bent tabs T may be heat staked for additional strength.

The base layer 50 of the lid 44 may be made of any plastic or polymer suitable for use in an airbag module cover application. However, the base layer 50 is preferably formed of thermoplastic olefin (TPO). Additionally, a groove 52 (shown in FIG. 1) may be formed in the base layer 50. The groove 52 is a pre-weakened tear line (or breaking point) that ruptures when the inflating airbag 10 exerts sufficient pressure on the lid 44. When the airbag 10 inflates, the groove 52 ruptures and the lid 44 swings open at the groove 52 to enable the inflating airbag 10 to deploy through the lid 44 into the vehicle passenger compartment 300.

The cover layer 60 of the lid 44 includes a substrate 65 and a surface layer 70. The substrate 65 forms the structure of the cover layer 65 so that the cover layer 60 is sufficiently durable and wear resistant. The substrate 65 may be made of any plastic or polymer suitable for use in an airbag module cover application. In an exemplary embodiment, the substrate 65 is formed of polycarbonate/ABS. As shown in FIGS. 1 and 3A-3C, the surface layer 70 is disposed on the substrate 65 and forms an outer (or top) layer of the lid 44. As a result, the surface layer 70 dictates the appearance of the cover layer 60. The surface layer 70 may be made of leather, a synthetic material (e.g., plastic), or a metallic material (e.g., aluminum, copper, brass, stainless steel, chrome, etc.). In an exemplary embodiment, surface layer 70 is made of aluminum. Additionally, the feel of the cover layer 60 may be customized based on the particular stylistic theme of the vehicle. For example, the cover layer 60 may be rigid so that the cover layer 60 is substantially impervious to deformation. Alternatively, the cover layer 60 may include cushioning so that the cover layer 60 has a pliable feel.

The surface layer 70 is configured to be disposed on the substrate 65 so that the surface layer 70 substantially covers a front surface 64 and a side surface 66 of the substrate 65 as shown in FIGS. 3A and 3B. The surface layer 70 may also cover a rear surface 68 of the substrate 65. In an exemplary embodiment (shown in FIG. 3A), the surface layer 70 is formed as a sheet, and the substrate 65 is formed as a panel. As shown in FIGS. 3A-3C, the surface layer 70 is attached to the substrate 65 by placing the surface layer 70 on the substrate 65 and folding (or wrapping) edges 73 of the surface layer 70 over and around edges 63 of the substrate 65. After the folding operation, the edges 73 of the surface layer 70 may be secured to the substrate 65 by crimping the edges 73 of the surface layer 70 to the rear surface 68 of the substrate 65. The surface layer 70 may also be secured to the substrate 65 by tacking, adhesive, and/or standard attachment hardware so that the surface layer 70 remains fixed to the substrate 65. According to an alternative embodiment, the surface layer 70 may be formed by sputtering a metallic material (e.g., chrome) onto the substrate 65.

According to an embodiment, the cover layer 60 may be formed as a single portion, as shown in FIG. 8. For example, the substrate 65 may be a one-piece panel, and the surface layer 70 may be a decal configured to adhere to the substrate 65. In this embodiment, the substrate 65 and the surface layer 70 each have a thickness that is sufficiently thin to enable the airbag 10 to deploy through the cover layer 60. As a result, a pre-weakened tear line does not need to be formed in the cover layer 60. Thus, the manufacturing process is simplified because a pre-weakened portion (i.e., groove 52) needs to be formed only on the base layer 50.

According to another embodiment, the cover layer 60 may include multiple portions as shown in FIG. 2. For example, the cover layer 60 may include a first portion 60 a and a second portion 60 b. Each of the first and second portions 60 a and 60 b includes a substrate 65 and a cover layer 70 substantially as described above. In this embodiment, the cover layer 60 is attached to the base layer 50 so that the first portion 60 a is disposed on one side of the groove 52. The second portion 60 b is disposed adjacent to the first portion 60 a but is located on an opposite side of the groove 52. As shown in FIG. 5, relative to the vehicle instrument panel 200, the first portion 60 a may be located above the groove 52 to form a first door (or panel), and the second portion 60 b may be located below the groove 52 to form a second door (or panel).

In this embodiment, because the first and second portions 60 a and 60 b are disposed adjacent to one another but on opposite sides of the groove 52, the first and second portions 60 a and 60 b of the cover layer 60 separate (or move apart) from one another when the base layer 50 ruptures at the groove 52. Thus, the cover layer 60 is not required to rupture in order for the airbag 10 to deploy. As a result, a wide variety of materials may be used to form the cover layer 60. For example, metals and other materials considered to be non-compliant for airbag applications may be used to form the cover layer 60. The expanded range of materials allows the design of various patterns that enhance the look and feel of the cover layer 60 for so that the cover layer 60 may be customized for a desired styling themes (e.g., leather wraps, patterns, graphic emblem designs, embossed metal, paint, etc.). Additionally, the cover layer 60 does not require additional processing to form a pre-weakened portion to facilitate airbag deployment.

According to an embodiment, a method of forming the module cover 40 for the airbag module 100 includes providing a base layer 50 having a groove (or pre-weakened portion) 52 for deploying the airbag 10, providing a substrate 65 including a first portion (or panel) and a second portion (or panel), providing a surface layer 70 including a first metal sheet and a second metal sheet, wrapping the first metal sheet around the first panel so that the first metal sheet substantially covers front and side surfaces of the first panel, wrapping the second metal sheet around the second panel so that the second metal sheet substantially covers front and side surfaces of the second panel, and attaching the first and second panels to the base layer.

Although the airbag module 100 shown in FIG. 1 is an airbag module for a passenger airbag device, the present invention is not limited to passenger airbag devices. Rather, the invention applies to any airbag device having an airbag module cover that is visible from a passenger compartment of a vehicle, including driver airbag devices, head/side curtain airbag devices, and side impact airbag devices.

Thus, according to embodiments of the present invention, an airbag module cover having an outer surface that forms part of a vehicle instrument panel is provided. The outer surface may be formed form a variety of materials not typically used in airbag module applications and enables the airbag module cover to have an appearance and feel that can not be achieved with conventional module covers.

Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims. 

1. A cover for an airbag module, comprising: at least a first layer, a second layer, and a third layer, wherein the first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle, wherein the second layer is disposed on the first layer, wherein the second layer includes a plurality of bosses configured to be inserted into corresponding apertures in the first layer and deformed to retain the second on the first layer.
 2. The cover of claim 1, wherein the third layer forms part of a vehicle instrument panel.
 3. The cover of claim 1, wherein the third layer is made of a metallic material.
 4. The cover of claim 3, wherein the metallic material includes aluminum.
 5. The cover of claim 3, wherein the metallic material is embossed.
 6. The cover of claim 1, wherein the third layer includes a decal.
 7. The cover of claim 1, wherein the second layer is formed of polycarbonate/ABS.
 8. The cover of claim 1, wherein only the first layer includes a predefined tear line for deploying an airbag.
 9. The cover of claim 1, wherein the first layer is formed of thermoplastic olefin.
 10. The cover of claim 1, wherein the bosses are made of plastic and are configured to be deformed by melting.
 11. A cover for an airbag module, comprising: at least a first layer, a second layer, and a third layer, wherein the first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle, wherein the second layer is disposed on the first layer, wherein the second layer includes tabs for connecting the second layer to the first layer.
 12. The cover of claim 11, wherein the second layer includes a bracket and the tabs project from the bracket.
 13. The cover of claim 12, wherein the bracket is disposed within a recess in the second layer.
 14. The cover of claim 12, wherein the bracket is molded into the second layer.
 15. The cover of claim 11, wherein the third layer forms part of a vehicle instrument panel.
 16. The cover of claim 11, wherein the third layer is made of a metallic material.
 17. The cover of claim 16, wherein the metallic material includes aluminum.
 18. The cover of claim 16, wherein the metallic material is embossed.
 19. The cover of claim 11, wherein the third layer includes a decal.
 20. The cover of claim 11, wherein the second layer is fanned of polycarbonate/ABS.
 21. The cover of claim 11, wherein only the first layer includes a predefined tear line for deploying an airbag.
 22. The cover of claim 11, wherein the first layer is formed of thermoplastic olefin.
 23. An airbag module, comprising: a cover including at least a first layer, a second layer, and a third layer, wherein the first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle, wherein the second layer is disposed on the first layer, wherein the second layer includes a plurality of bosses configured to be inserted into corresponding apertures in the first layer and deformed to retain the second on the first layer, wherein the airbag module is configured to be positioned in a vehicle so that the cover of the module forms a portion of a vehicle instrument panel and wherein the third layer of the cover includes a metal top layer configured to separate into at least two pieces to allow an airbag to deploy therethrough.
 24. An airbag module, comprising: a cover including at least a first layer, a second layer, and a third layer, wherein the first layer includes a predefined tear line and the third layer is configured to face into a passenger compartment of a vehicle, wherein the second layer is disposed on the first layer, wherein the second layer includes tabs for connecting the second layer to the first layer, wherein the airbag module is configured to be positioned in a vehicle so that a cover of the module forms a portion of a vehicle instrument panel and wherein the third layer of the cover includes a metal top layer configured to separate into at least two pieces to allow an airbag to deploy therethrough. 